Liquid-crystal display (LCD) devices have become the mainstream display device and are mainly applied to LCDs for computers, large-scale LCD TVs and the like. As LCD panels per se do not emit light spontaneously, the display effect can only be achieved when the LCD panels are used together with backlights. In the early stage of the development of the LCD devices, the mainstream backlights adopt cold cathode fluorescent lamps (CCFL). But CCFLs have insufficient mechanical strength and poor color reproducibility, and do not meet the environmental requirements as they contain mercury. In recent years, CCFL backlights have been gradually replaced by light-emitting diode (LED) backlights. As compared with CCFL backlights, LED backlights have the advantages of not containing toxic substances and having high mechanical strength, long service life and the like. As the LED backlights have so many advantages, most display devices used currently adopt LEDs as backlight systems.
Although LED backlights have the above advantages, the color gamut range of the LED backlights is only 70 to 80 percent of the standard color gamut. There is still much room for improvement in color gamut range.